Polycrystalline diamond (PCD) materials and PCD elements formed therefrom are well known in the art. Conventional PCD is formed by combining diamond grains with a suitable solvent catalyst material and subjecting the diamond grains and solvent catalyst material to processing conditions of extremely high pressure/high temperature (HPHT). During such HPHT processing, the solvent catalyst material promotes desired intercrystalline diamond-to-diamond bonding between the grains, thereby forming a PCD structure. The resulting PCD structure produces enhanced properties of wear resistance and hardness, making PCD materials extremely useful in aggressive wear and cutting applications where high levels of wear resistance and hardness are desired. The fast evolution of PCD elements as used in applications such as bits for drilling subterranean formations result in longer drilling time and wider application range. In such use, PCD elements may be exposed for a longer total drilling time in more corrosive drilling environments.
Solvent catalyst materials that are typically used for forming conventional PCD include metals from Group VIII of the periodic table, with cobalt (Co) being the most common. Conventional PCD can comprise from 85 to 95 percent by volume diamond and a remaining amount of the solvent catalyst material. The solvent catalyst material is present in the microstructure of the resulting PCD material within interstices or interstitial regions that exist between the bonded together diamond grains.
The solvent catalyst material is typically provided during the HPHT process from a substrate that is to be joined together with the resulting PCD body, thereby forming a PCD compact. When subjected to the HPHT process, the solvent catalyst material within the substrate melts and infiltrates into the adjacent diamond grain volume to thereby catalyze the bonding together of the diamond grains. In such HPHT process, the solvent metal catalyst is typically supplied from the substrate, forming a metal catalyst rich zone adjacent to the interface between the PCD body and the substrate.
It is desired that polycrystalline diamond constructions be engineered in a manner so as to minimize or eliminate the unwanted corrosion or erosion of the PCD construction, to thereby minimize or eliminate any delamination or other failure mode that may be associated with conventional PCD constructions.